In the fabrication of heat exchangers, extruded flat tubing with internal webs is frequently used to conduct a working fluid through a path in the heat exchanger. Sometimes, numerous tubes are networked together to form a plurality of paths. Regardless of the type of heat exchanger being made, and especially when making heat exchangers for automotive air conditioning units, it is very undesirable to generate burrs or metal fragments during the cutting of the tubing into usable lengths since the fragments, if not totally removed, clog and damage components of the system. Although rotary saw blades are commonly used in the industry for cutting the tubing, tubing cut in that manner results in numerous burrs and fragments. It is also known in other arts to cut long pieces of material into shorter length by scoring or grooving the material and bending the piece to break it at the score.
In many heat exchangers, the tubes are inserted into a common manifold and brazed to form a one-piece assembly. Burrs make tube insertion into the manifold very difficult and time consuming. The dimensional tolerance range of the extruded tubing is greater than that allowed in the braze operation or accepted by the manifold. For satisfactory installation into the manifold, the perimeter of the ends of the tubes must be sized down to an acceptable dimension for insertion. It is important, too, that the braze joint formed not possess any voids which may form leaks. In particular, the perimeter of the tube must be sized to fit snugly into the hole of a manifold or other end fitting.
It is seen then that there exists a need for an apparatus and method for sizing extruded tubing to desired perimeter dimensions and cutting the sized tubing to desired lengths without creating debris.